1. WLTP-DTP-LabProcICE-209
4WD dyno specification ~ Integration of distance gap between front and rear roller ~

2. Point of discussion - Japanese proposal - 2.3.1.4.
The difference in distance covered by the front and rear rolls shall be less than 0.2 per cent of the driven distance over the WLTC. The absolute values shall be integrated for the calculation of the total difference in distance over the WLTC.
Whole test period
Partial test period
MAHA
(A)
Ford
(B)
JPN1
(B)’
JPN2
(C)
stringency
(B)’ > (A)
*need to discuss (B)
(A) > (C)
* refer to footnote
spec (C)
50cm/s
(=0.1m/200ms)
Purpose of spec (C)
To prevent any fail safe action of vehicles due to descrepancy of front/rear tire speed.
spec (A)
4.4cm/s
(=0.16km/h)
Purpose of spec (B)’
To prevent excessive friction due to torque transmission mechanism operation.
spec (B)’
1.3cm/s*
spec (B)
0.13cm/s*
end of test cycle
200ms 1s
*Based on JC08
(approx. 8.2km, 1200sec)
0.2%  1.3cm/sec
0.02%  0.13cm/sec
This figure does not indicate each specification perfectly.
The purpose of this figure is to show relative stringency of each specification roughly.

3. Integration by absolute values
Supplementary material about “Ratio of difference in driving distance’（B)、（B)‘
(B)’
(B)

4. Reason of Japanese proposal
The reason of using absolute values of front-rear roller speed difference in (B)'
Regardless of polarity of front-rear roller speed difference, energy losses are generated in torque transmission mechanism.
It is necessary to use absolute values of front-rear roller speed difference to;
- evaluate the effect of energy losses in torque transmission mechanism correctly and,
- prevent the fuel consumption by dyno. performance from taking into vehicle specification.